Supplementary Materialsnanomaterials-08-00518-s001. and RS/yeast film layers onto a self-adherent paraffin substrate, was used for the realization of heat-responsive wrinkles by exploiting the high thermal expansion of the paraffin substrate that regulates the applied strain, resulting in a switchable coating morphology from the wrinkle-free state to a wrinkled state if the food temperature overcomes a designed threshold. We envision that such efficient and smart coatings can be applied for the realization of smart packaging that, through such a temperature-sensing mechanism, can be used to control food storage Mouse monoclonal to FGR conditions. yeast cells were fermented by nutrient addition into a silk fibroin solution, the regenerated silk shows a higher content of beta-sheet structures. Moreover, the microorganism growth increased the cell density and reduced the porosity of the RS membrane, limiting the exchange of water and gas diffusion. As conceptual proof, we demonstrated as an example that this deposition of such a living coating on fruits helps the preservation of their shelf-life. Finally, we demonstrate that RS-based film layers can be laminated onto a paraffin wax substrate for the realization of temperature-responsive bilayer system. 2. Materials and Methods For the preparation of the RS film, commercial silk cocoons were boiled for 1 h in a distillated water solution of 0.025 wt % NaHCO3 Riociguat novel inhibtior rinsed with distilled water every 30 min to remove the sericin. According to the method adopted by Kaplan et al. , the degummed silk (i.e., 0.2 g) was then added to a CaCl2 (i.e., 0.14 g) and CH2O2 (formic acid) (i.e., 20 mL) solution mixture and stirred overnight at 40 C to yield a 1 wt % solution. A water solution (50 mg/mL) of a (Lesaffre Italia S.p.A. S. Quirico, Tre Casali, Italy)-based beer yeast extract was prepared separately by mechanical stirring at 30 C for 1 h. After that, 0.4 g of sucrose was added to 20 cc of water to start the fermentation. The water solution of fermenting yeast was then added to the silk fibroin Riociguat novel inhibtior solution. RS/yeast films were prepared by leaving the silkCyeast solution to evaporate for 12 h in a polystyrene Petri dish (diameter 15 cm). The growth of yeast cells was monitored by the optical density (OD) method, measuring the absorbance at a wavelength of 600 nm and a temperature of 30 C of the yeast and RS/yeast solutions in sucrose growth medium. The morphology of Riociguat novel inhibtior the films was investigated by optical and field emission scanning electron microscopy (FESEM). Fourier transform infrared (FTIR) analysis was performed in a Jasco FTIR FT/IR-615 spectrometer equipped with an ATR mode in the wave number range from 400 to 4000 cm?1. The spectra were deconvoluted by firstly smoothing the signal with a polynomial function with a 15-point SavitskiCGolay smoothing function, subtracting a linear baseline, and applying a Gaussian deconvoluting curve by Origin 9 software. X-ray diffraction (XRD) was performed using a Bruker D8 Advance diffractometer with a radiation source of CuK and wavelength = 0.154 nm operated at 40 kV and 40 mA. The incidence angle (2) was varied between 2 Riociguat novel inhibtior and 60 and the scan rate was 0.02/s. The tensile properties of films were measured using a universal tensile testing machine (Lloyd Instr. LR30K) with a 50 N static load cell. Three specimens of each sample were cut into strips Riociguat novel inhibtior (30 mm 12 mm 0.08 mm). The gauge length was 20 mm, and the extension rate was set at 2 mm/min. The effect of different types of coatings on bananas freshness was evaluated by monitoring the colour change through time-lapse photography. The water permeability was decided after soaking a sponge in water and subsequently dip-coating the sponge in RS and RS/yeast solutions. The variation of the weight was monitored at different hours with a standard laboratory balance (Mettler Toledo AB135-S/FACT). The weight variation was calculated as an average of three measurements for each coating. The respiration rate of bananas was evaluated by monitoring the CO2 production. In brief, bananas were placed in a sealed FTIR chamber and the production of CO2 was monitored by measuring the evolution of the CO2 absorption peak over a period of 7 days (see Supplementary Material Physique S1). This measurement takes into account the initial background performed in air to remove the initial contribution of the carbon dioxide moisture of the air. For the adopted transfer print process to realize the bilayer system, regenerated silk was transferred to a Parafilm film (Parafilm M?, Bemis Company Inc., Neenah, WI, USA) through a direct transfer process, which consists.